Pressure balanced carburetor



Oct. 7, 1958 H. w. MCCLAIN 2,855,284

PRESSURE BALANCED CARBURETOR Filed Feb. 5, 1957 way/m AQIIV/IZ/WFQIM of an engine (not shown).

United States PatentO PRESSURE BALANCED CARBURETOR Harry W. McClain, Long Beach, Calif.

Application February 5, 1957, Serial No. 638,381 Claims. c1. 48-184) This invention relates to a pressure balanced carburetor wherein fuel under pressure is introduced into one side of a flexible diaphragm, and the pressure of the incoming air is exerted against the other side of this same diaphragm; the fuel metering valve being mounted on the diaphragm and caused to move relative to a seat whereby the amount of fuel introduced into the engine is varied. An object of my invention is to provide a novel pressure balanced carburetor including a fuel intake chamber into which the fuel under pressure is admitted. One side of this chamber is enclosed by a flexible diaphragm, and the air intake valve of the carburetor is attached to this diaphragm toexert a pressure thereon opposite to the pressure of the incoming fuel.

Another object of my invention is to provide a novel pressure balanced carburetor of the character stated, which is simple in construction, relatively inexpensive to manufacture, and which is simple to adjust in that the metering valve is adjusted by a single screw.

Still another object of my invention is to provide a novel pressure balanced carburetor in which the proper fuel supply is maintained, as well as the proper fuel air ratio, irrespective of the fluctuation of air pressure and also slight variations in the fuel pressure.

Still another object of my invention is to provide a novel pressure balanced carburetor in which the pressure actuated diaphragm of the carburetor is also acted upon by the vacuum of the intake manifold of the engine to assist in maintaining the proper balance between the fuel pressure and the external air pressure.

Other objects, advantages and features of invention may appear from the accompanying drawing, the subjoined detailed description and the appended claims.

In the drawing:

Figure 1 is a side elevation of my pressure balanced carburetor.

Figure 2 is a longitudinal sectional view of the same.

Figure 3 is a sectional view taken on line 33 of Fig. 2. p

Referring more particularly to the drawing, my pressure balanced carburetor is adapted to supply gaseous fuel to an engine, and particularly a hydrocarbon gaseous fuel such as propane, or the like, and which is normally supplied to the carburetor under a substantially constant pressure. My carburetor includes a housing 1, which housing includes the flanged coupling 2 by means of which the carburetor is bolted to the intake manifold The housing 1 of the carburetor includes an air intake opening 3 through which air is drawn to admix with the incoming fuel. as will be subsequently described. The side of the housing 1 opposite the air intake 3 is open and a fitting 4 is mounted in this opening, preferably by means of the studs 5 or otherwise. The fitting 4 is preferably an integral casting and includes a chamber 6 therein, and the chamber 6 is aligned with the horizontal center line of the housing 1, or substantially so. A fuel intake pipe 7 extends into the chamber 6 and admits gaseous fuel under pressure into this chamber. A flexible diaphragm 8 closes one side of the chamber 6 and the fuel pressure in this chamber tends to flex that diaphragm towards the left, as shown in Figure 2. A tube 9 is flared outwardly at its lower end, as shown at 10, to form a vacuum chamber 11. This vacuum chamber 11 is arranged opposite to the chamber 6, and the diaphragm 8 is positioned between these two chambers as will be evident from Figure 2. The flared portion 11 of the tube 9 is also bolted to the fitting 4 by means of bolts or the like 12, thus securely attaching the tube 9 to the fitting and positioning that tube in horizontal axial alignment within the housing 1. A cylindrical rod 13 is fixedly attached at one end to the diaphragm 8, and the rod is slidable within the tube 9 and accurately fits this tube so that the rod may freely move within the tube as the diaphragm 8 flexes.

A disc valve 14 is mounted within the air intake 3, and this valve opens and closes the intake 3 and proportions the flow of air therethrough in the following manner: The valve 14 includes an integrally formed cylinder 15 which surrounds the tube 9 and is slidable thereon. The outerend of the cylinder 15 is closed by the wall 16 and an adjusting screw 17 i threaded through this wall, and the inner end of the screw is attached to the outer end of the rod 13. The method of attaching the screw the movement of the cylinder15 in both directions and still the screw 17 can be rotated to adjust the rod 13 relative to the cylinder 15 and the air valve 14 thereon. The screw 17 can be clamped against accidental rotation by means of the clamp screw 19.

The fitting 4 is provided with a fuel port 21 which is arranged between the chamber 6 and the fuel passage 21, substantially as shown. The fuel passage 21 in the fitting 4 conducts the incoming fuel into the housing 1 and into a pipe 22 which is arranged within the housing 1, and opens into the coupling portion 2 of the housing so as to direct the fuel past the throttle valve 23 and thence into the intake manifold of the engine,

The flow of fuel through to the port 20 is controlled by means of the tapered valve 24; which is mounted on the inner end of the rod 13 and is thus also fixedly mounted on the diaphragm s; The tapered valve 24 has an adjustable connection to the rod 8, that is, so that the valve may adjust itself relative to the port 20 and may properly seat itself in the closed position of the Carburetor. This connection ofthe valve to the rod 13 may be by means of the spring wire 25, which wire is secured at one end to the rod 13 and the other end is bent around the valve 24 substantially as shown, A small bleed port 26 is provided in the wall of the chamber 11 so that the partial vacuum presentin the intake 'manifold Tof'the engine will evacuate the chamber 11, and thus tend to flex the diaphragm 8 in the same direction as that diaphragm is urged by the fuel pressure in the fuel chamber 6.

In operation:

Gaseous fuel under pressure passes from the intake pipe 7 into the chamber 6. The pressure of the fuel against the diaphragm 8 tends to move that diaphragm towards the left as shown in Figure 2, and thus close the valve 24 in the port 2t). As soon as the engine starts, air flows into the housing 1 past the valve 14, causing that valve to move towards the right as viewed in Figure 2, and this movement of the air valve will be transmitted to the rod 13 and thence to the Valve 24 to unseat that valve and permit fuel under pressure to pass through the port 20 and thence through the channel 21, the pipe 22, and into the throat of the carburetor where it mixes with the incoming air. The inward movement of the air valve 14 is opposed by the pressure of the fuel in the chamber 6, and also by the partial vacuum within the chamber 11. The valve 24 may be adjusted relative to the port by the adjusting screw 17 which moves the rod 13 horizontally within the tube t, thus permitting accurate positioning of the fuel valve with relation to the position of the air valve 14.

Having described my invention, I claim:

1. A pressure balanced carburetor comprising a housing, said housing having an air intake opening therein, and a flanged coupling, said flanged coupling defining a mixing throat, a fitting attached to the housing opposite said air intake opening, said fitting including walls defining a fuel chamber, a flexible diaphragm forming one wall of said fuel chamber, said fitting having a fuel outlet passage therein, said fuel outlet passage extending into the housing adjacent the mixing throat, said fitting having a fuel port between said fuel chamber and the fuel outlet passage, a valve positioned in said fuel port, means securing said valve to said diaphragm, a fuel intake pipe extending into said fuel chamber, a rod, means securing one end of said rod to the diaphragm, an air valve positioned in said air intake opening, and means securing said air valve to the rod at the end opposite said diaphragm.

2. A pressure balanced carburetor comprising a housing, said housing having an air intake opening therein,

and a flanged coupling, said flanged coupling defining a mixing throat, a fitting attached to the housing opposite said air intake opening, said fitting including walls defining a fuel chamber, a flexible diaphragm forming one wall of said fuel chamber, said fitting having a fuel outlet passage therein, said fuel outlet passage extending into the housing adjacent the mixing throat, said fitting having a fuel port between said fuel chamber and the fuel outlet passage, a valve positioned in said fuel port, means securing said valve to said diaphragm, a fuel intake pipe extending into said fuel chamber, a rod, a tube surrounding the rod, said rod being slidable in the tube, means securing one end of said rod to the diaphragm, an air valve positioned in said air intake opening, and means securing said air valve to the rod at the end opposite said diaphragm.

3. A pressure balanced carburetor comprising a housing, said housing having an air intake opening therein, and a flanged coupling, said flanged coupling defining a mixing throat, a fitting attached to the housing opposite said air intake opening, said fitting including walls defining a fuel chamber, a flexible diaphragm forming one wall of said fuel chamber, said fitting having a fuel outlet passage therein, said fuel outlet passage extending into the housing adjacent the mixing throat, said fitting having a fuel port between said fuel chamber and the fuel outlet passage, a valve positioned in said fuel port, means securing said valve to said diaphragm, a fuel intake pipe extending into said fuel chamber, a rod, a tube surrounding the rod, said rod being slidable in the tube, means securing one end of said rod to the diaphragm, an air valve positioned in said air intake opening, and means securing said air valve to the rod at the end opposite said diaphragm, said tube being flared outwardly at its end adjacent the diaphragm, the flared end of the tube defining a vacuum chamber on one side of said diaphragm and opposite said fuel chamber, said flared part of the tube having a bleed port therein to evacuate said vacuum chamber.

4. A pressure balanced carburetor comprising a housing, said housing having an air intake opening therein, and a flanged coupling, said flanged coupling defining a mixing throat, a fitting attached to the housing opposite said air intake opening, said fitting including walls defining a fuel chamber, a flexible diaphragm forming one wall of said fuel chamber, said fitting having a fuel outlet passage therein, said fuel outlet passage extending into the housing adjacent the mixing throat, said fitting having a fuel port between said fuel chamber and the fuel outlet passage, a valve positioned in said fuel port, means securing said valve to said diaphragm, a fuel intake pipe extending into said fuel chamber, a rod, means securing one end of said rod to the diaphragm, an air valve positioned in said air intake opening, a tube surrounding the rod, said rod being slidable in the tube, a cylinder on the air valve, said cylinder being slidable on the tube and adjusting screw threaded through the end wall of the cylinder, and means securing the inner end of the adjusting screw to the rod.

5. A pressure balanced carburetor comprising a housing, said housing having an air intake opening therein, and a flanged coupling, said flanged coupling defining a mixing throat, a fitting attached to the housing opposite said air intake opening, said fitting including walls defining a fuel chamber, a flexible diaphragm forming one wall of said fuel chamber, said fitting having a fuel outlet passage therein, said fuel outlet passage extending into the housing adjacent the mixing throat, said fitting having a fuel port between said fuel chamber and the fuel outlet passage, a valve positioned in said fuel port, means securing said valve to said diaphragm, a fuel intake pipe extending into said fuel chamber, a rod, means securing one end of said rod to the diaphragm, an air valve positioned in said air intake opening, a tube surrounding the rod, said rod being slidable in the tube, a cylinder on the air valve, said cylinder being slidable on the tube and adjusting screw threaded through the end wall of the cylinder, and means securing the inner end of the adjusting screw to the rod, said tube being flared outwardly at its end adjacent the diaphragm, the flared end of the tube defining a vacuum chamber on one side of said diaphragm and opposite said fuel chamber, said flared part of the tube having a bleed port therein to evacuate said vacuum chamber.

Poinsignon June 20, 1944 Peduzzi Dec. 28, 1954 

1. A PRESSURE BALANCED CARBURETOR COMPRISING A HOUSING, SAID HOUSING HAVING AN AIR INTAKE OPENING THEREIN, AND A FLANGED COUPLING, SAID FLANGED COUPLING DEFINING A MIXING THROAT, A FITTING ATTACHED TO THE HOUSING OPPOSITE SAID AIR INTAKE OPENING, SAID FITTING INCLUDING WALLS DEFINING A FUEL CHAMBER, A FLEXIBLE DIAPHRAGM FORMING ONE WALL OF SAID FUEL CHAMBER, SAID FITTING HAVING A FUEL OUTLET PASSAGE THEREIN, SAID FUEL OUTLET PASSAGE EXTENDING INTO THE HOUSING ADJACENT THE MIXING THROAT, SAID FITTING HAVING A FUEL PORT BETWEEN SAID FUEL CHAMBER AND THE FUEL OUTLET PASSAGE, A VALVE POSITIONED IN SAID FUEL PORT, MEANS SECURING SAID VALVE TO SAID DIPHRAGM, A FUEL INTAKE PIPE ONE END OF SAID ROD TO THE DIAPHRAGM, AN AIR VALVE POSITIONED IN SAID AIR INTAKE OPENING, AND MEANS SECURING SAID AIR VALVE TO THE ROD AT THE END OPPOSITE SAID DIAPHRAGM. 